BIOLOGY: CONDITIONS on EARLY EARTH?

Question

in what way were conditions on the early earth different from those on modern earth?

a) the early earth had no water
b) the early earth was much cooler
c) the early earth had an oxidizing atmosphere
d) less ultraviolet radiation penetrated the early atmosphere
e) the early atmosphere had significant quantities of CH4 and NH3

Answer 1

Tip: You'll learn a lot more by using Google to type in key phrases (like "early earth atmosphere") than just asking for the right answer here. Please don't just write down the answer (or you will be dead on a test) ... understand *WHY* it is the right answer.

You need to eliminate them one by one. (a) and (b) you should be able to eliminate off the top of your head ... (c), (d), and (e) you need to research more (see source), or read your text book.

(a) The early earth had lots of water (as much as it does today).
(b) The early earth was a lot hotter (fresh from the oven ... lots of volcanic activity).
(c) The early earth did not have an oxidizing atmosphere, but the opposite, a "reducing" atmosphere (Google "oxidizing atmosphere" and "reducing atmosphere" to learn what these mean ... but basically, the early atmosphere had no oxygen, which is toxic to organic chemicals).
(d) The early earth had much more UV radiation ... this is because it is again oxygen (in the form of O3, or ozone), that filters out much of the UV radiation ... so before there was atmospheric oxygen, there was a lot more UV radiation.
(e) The early earth did have more CH4 (methane) and NH3 (ammonia). (See source.)

So the answer is (e).

Answer 2

a) is wrong, because the first life start from water.

b) is wrong. because earth was hot ( not sure but i think so)

c) dont know

d) wrong. because the earth didnt had the ozon layer, so it was full of ultraviolet radiations.

e) should be true, because for sure there is quantities for any thing in the world. and CH4 and NH3 where be found in the early earth.

Answer 3

I think most scientists believe that there were higher levels of methane and ammonia